The Autism – Tics, AD/HD, and other Comorbidities inventory (A-TAC) is a comprehensive interview for
evaluating problems related to autism spectrum disorders (ASD), tic disorders, attention-deficit/hyperactivity disorder
(AD/HD), and common comorbid conditions in children and adolescents. A-TAC telephone interviews were administered
to parents of 2,957 children aged nine- or twelve-years, representing one in each twin pair included in the populationbased
Child and Adolescent Twin Study in Sweden (CATSS).
A total of 16.4% were screen-positive for one or several of the targeted disorder, 1.3% for ASD and 5.6% for AD/HD. All
types of problems were more common among boys, with the exception of those related to “eating habits”. They were all
dimensionally/continuously distributed, highly inter-correlated, and overlapped across types. They aggregated in three basic
factors corresponding to externalizing/disruptiveness, socio-communicative problems, and compulsiveness.
Population-based data on problems in children thus challenge current categorical diagnostic definitions, calling for dimensional
and complementary models of problem descriptions.